Thermal ink jet printers, provide an effective means of propelling ink jet inks onto various media including paper. These printers can accomplish this by using resistive heater elements for heating the ink to a boil, and propelling the ink through an overlying orifice plate. Such printers as typified by the Hewlett-Packard DeskJet™ and DesignJet™ printers, are desirable for use for several reasons. For example, thermal ink jet printers have a relatively fast throughput while being relatively inexpensive to run. Additionally, these printers are relatively easy to use, and the ink is easily replaced.
There are several reasons that ink-jet printing has become a popular way of recording images on various media surfaces, particularly paper. Some of these reasons include low printer noise, capability of high-speed recording, and multi-color recording. Additionally, these advantages can be obtained at a relatively low price to consumers. However, though there has been great improvement in ink-jet printing, accompanying this improvement are increased demands by consumers in this area, e.g., higher speeds, higher resolution, full color image formation, increased stability, new applications, etc. In addition to these challenges, there is increased market pressure to provide ink-jet inks for new and creative applications.
Many experimental electro-conductive inks have been and are being produced for various purposes. In order to produce a conductive ink, conductive substances are integrated into the ink system. Pigments and/or dyes can be optionally added if the desire is to visualize the conductive path being created. As a practical matter, in order for an ink to be conductive, the conducting substances should be present in the ink matrix such that the individual particles are large enough and close enough together to functionally allow for current flow. Appropriate substances can include first-grade conductors such as metal and precious metal powder and/or carbon powder. Though metal and precious metal powders generally provide for higher conductivity that carbon powder, they also are more prone to oxidation, corrosion, and in some cases, migration. Precious-metal powders can also be expensive. Conversely, carbon, does not exhibit these problems.
No matter what electro-conductive material is used to create the electro-conductive ink, by selecting the appropriate ink vehicles and/or other components, e.g., polymers, surfactants, etc., easy processing, good adhesion and high mechanical and chemical resistance can be achieved.
In the scented ink area, many different types of inks have been prepared that can emit odors. For example, a printed image known by its common name “scratch and sniff” is one such technology. The basic idea behind scratch and sniff technology is to take the aroma generating chemical and encapsulate it in gelatin or plastic microspheres through a process known generally as microencapsulation. Such gelatin or plastic spheres can be as small as a few microns in diameter. Thus, when the microspheres are mechanically ruptured by scratching, the odor is released.
Other odor-containing inks have also been prepared that contain an odor that is detectable when exposed to a surrounding environment. Such inks have been used in felt-tipped pens wherein the odor is not noticeable to the user until a pen cap is removed from the pen and/or the ink is presented on a substrate. However, the odor of such an ink, once printed on a substrate, does not last for a significant period of time as may be desired by the user.